a. Field of the Invention
The present invention relates to a telephotographic lens system having a short total length, a numerical aperture of F/2, a telephoto ratio of 1.07 to 1.08 and wherein spherical aberration and astigmatism are favorably corrected.
B. Description of the Prior Art
Telephotographic lens systems consisting of small number of lens elements and having large aperture ratios as is exemplified by Japanese Patent Publication No. 9466/55 are conventionally known to the public. As can judged from this example, however, conventional telephotographic lens systems are not sufficiently satisfactory in their compactness and other respects.